Prefix meaning former, old, or ex- (used in compounds to indicate something that used to be).
旧友とは年に一度会っている。
I meet an old friend once a year.
会社の旧本社は駅前にあるビルだ。
The company's former headquarters is the building in front of the station.
古い町並みが残る旧市街地を歩いた。
I walked through the old downtown area where the historic streets remain.
A noun use referring to old things, customs, or practices (often in expressions like 'old/traditional').
旧来の習慣が今も地域で続いている。
Traditional customs still continue in the region.
改革の前は旧のやり方が主流だった。
Before the reform, the old methods were mainstream.
Refers to bygone times or former eras (used in compounds like 'old era').
旧時代の暮らしは今とはずいぶん違う。
Life in the old days was quite different from today.
旧世代の価値観を見直す必要がある。
There's a need to reassess the values of the older generation.
An abbreviated usage referring to Japan's old (lunisolar) calendar (old calendar).
今年の旧（旧暦）の正月は2月に当たる。
This year's lunar new year (old calendar) falls in February.